Level Select (back up file first!!):
Use a text editor to edit the "mission.dat" or "mission.cfg" file in the game directory. Replace all characters in the file with "1111111111". Any level may now be selected for game play.
During gameplay type thunder or winter for version 1.51 to activate cheats

Code Description:
ALT + F7 reveal the entire map
ALT + 1 through ALT + 6 change the speed of the game (ALT + 1 is slowest and ALT + 6 is fastest)

Additional HQs:
After enabling the cheat code above you can click on any are suitable for a HQ and you can build it.